Adding vent, where should we put it?

Our coop is 4x8. There is a window on the right side of the front wall (8' side). The roost runs along the back wall. The pop door is in the right 4' wall. Should the vent be placed on the back 8' wall or the left 4' wall?

If it's just a regular old 8 x 16" vent, I don't think it'll matter a whole lot. From which direction do your prevailing winter winds blow?? I'd probably put it opposite from them, so it'll do its purpose, but won't allow icy winds to blow in.

I think a lot depends on where you live. In Texas, the heat is incredible. We have a prevailing southerly wind that needs to be taken advantage so I put 2 large 2'x2' flap type windows that hinge at the top. when propped open the flap serves as a shade in the afternoon so the sun doesn't blast in while taking advantage of the southerly breeze.

I put 2 smaller shed type glass windows on the north wall that allows the breeze to escape and minimizes the winter northers that blow here. I've also got vents between the rafters (covered in hardware cloth) on the east and west that help to ventilate as well.